Port 8888 (HTTP alternate / Jupyter)

Default port of Jupyter Notebook and JupyterLab; also used by many proxies and dev tools.

Registered (user) port, 1024-49151 TCP Development tools Expose only to trusted sources

What port 8888 is used for

Default port of Jupyter Notebook and JupyterLab; also used by many proxies and dev tools.

Security: should port 8888 be open?

Expose only to trusted sources. An exposed Jupyter server without a token is remote code execution by design; attackers mine crypto on them. Keep the token or password on and reach it through SSH tunnels.

IANA assignment

Service nameProtoDescriptionAssigneeReference

ddi-tcp-1 TCP NewsEDGE server TCP (TCP 1) Fred Yao -

ddi-udp-1 UDP NewsEDGE server UDP (UDP 1) Fred Yao -

Check what is listening on port 8888

Linux: is anything listening on TCP 8888?

sudo ss -tlnp 'sport = :8888'

Linux / macOS: which process owns the port

sudo lsof -nP -i :8888

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':8888 '

Windows (Command Prompt)

netstat -ano | findstr :8888

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 8888 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine

nc -vz -w 5 HOST 8888

From Windows

Test-NetConnection HOST -Port 8888

Allow only trusted sources on port 8888 in the firewall

Replace 203.0.113.10 with the address or network you trust. With ufw, make sure the default incoming policy is deny.

ufw (one trusted source)

sudo ufw allow from 203.0.113.10 to any port 8888 proto tcp

iptables

sudo iptables -A INPUT -p tcp --dport 8888 -s 203.0.113.10 -j ACCEPT
sudo iptables -A INPUT -p tcp --dport 8888 -j DROP

nftables

sudo nft add rule inet filter input ip saddr 203.0.113.10 tcp dport 8888 accept
sudo nft add rule inet filter input tcp dport 8888 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'TCP 8888 trusted' -Direction Inbound -Protocol TCP -LocalPort 8888 -RemoteAddress 203.0.113.10 -Action Allow

All port numbers · Open port checker
Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.